Engineered tissues or organs can be produced ex vivo (for example in a bioreactor) and implanted into a host (e.g., a human patient) in order to replace or supplement an injured, diseased, or otherwise failing organ in the host. Engineered tissues or organs can be produced in a bioreactor by cellularizing a support structure referred to as a scaffold. Current techniques for producing scaffolds that can be cellularized ex vivo include methods that involve decellularizing a natural organ or tissue to produce an acellular scaffold of natural structural material, or methods that involve configuring a synthetic material to mimic a shape of a natural scaffold.